The local environment regulates biogeographic patterns of soil fungal communities on the Loess Plateau

Soil fungi play critical ecological roles in terrestrial ecosystem function, soil formation and element cycles. However, the biogeography of soil fungi in the forest ecosystem is poorly understand, especially in arid or semiarid areas. Here, a regional scale study in an arid area was conducted on the Loess Plateau to illustrate the geographic distributions of soil fungi and their driving forces. The results showed that Ascomycota, Basidiomycota and Zygomycota were the most dominant phyla in 24 sample sites. Fungal Shannon diversity and OTUs richness were significantly correlated with mean annual precipitation (MAP), total soil nitrogen (TN), ammonium nitrogen (NH4N) and soil organic carbon (SOC) levels. The decay-curve analysis demonstrated that soil fungal Bray-Cutis dissimilarities were significantly regressed with geographic distance, revealing that the soil fungal community structure was affected by historical factors. Variation partitioning analysis revealed that the soil properties (15%) contributed more to the fungal community variations than geographic distance (9%). Additionally, there were many predictors of soil fungi geography that were not detected. These results suggest that the fungal geography on the Loess Plateau is mainly regulated by soil properties or other unmeasured variables. Such findings advance our understanding of fungal diversity patterns on the Loess Plateau, which will help us better understand the functions and services in underground ecosystems in arid areas.